The former head of Catalonia's regional government and two of his aides went on trial Monday in Barcelona for ignoring a Constitutional ban and going ahead with a vote on the region's independence from Spain.The five-day trial is likely to inflame longstanding tensions between the central government and the supporters of separatism in the wealthy northeastern region of 7.5 million people.Artur Mas, who stepped down as president of the regional government last year, faces a 10-year ban from holding public office for disobedience and wrongdoing.Prosecutors are also calling for fines and a nine-year disqualification from politics for former regional vice president Joana Ortega and education councilor Irene Rigau, both accused in the same case of aiding with the November 2014 vote.Organizers at the time said 80 percent of the 2.3 million Catalans who cast a ballot voted to support creating a Catalonian state independent from Spain.The mock referendum was deemed illegal by Spain's Constitutional Court five days earlier, but Mas and other officials gathered support from more than 40,000 volunteers who opened schools and installed voting stations."We are holding our head high, convinced that we did the right thing," Mas said Sunday. "We would do the same thing again."On Monday, independence supporters staged a show of force, with thousands accompanying the defendants through downtown Barcelona before the court appearance.Protesters formed a 200-meter corridor in the last stretch leading to Catalonia's High Court, cheering and waving unofficial flags of independence. "We shall overcome" was the slogan on some banners in English, with a gigantic display reading "Love democracy."Mas declined to answer questions from the prosecution during Monday's hearing. In replies to inquiries by his own defense lawyers, he blamed Spain's central authorities for not doing more to stop the vote.He said his cabinet's aim "wasn't holding a vote that was immediately legally binding but rather knowing people's opinion after massive protests in past years."Polls consistently show that residents in Catalonia who want to break from Spain are a minority, although the ranks of those who do want a vote on separatism have been swelling since the 2008 economic crisis.Some lifelong secessionists argue that only a separate Catalan state could protect their culture and their language— which is spoken side by side with Spanish.In defiance of the Constitutional ban and a fierce opposition by Spain's ruling conservative Popular Party, a new regional government in Catalonia has promised to pass laws to enable a legally binding referendum later this year. But it's unclear how a new vote would be different from the 2014 vote that was only seen as symbolic.The national government has said that no vote will be allowed and has pledged to boost investments in Catalonia.But only after securing a second term with a minority government in November did Prime Minister Mariano Rajoy launch an offer for dialogue in all matters except on a referendum on separatism.Deputy Premier Soraya Saenz de Santamaria said Monday the government would consider investing in Catalan infrastructure and public services but declined to comment directly on the trial, saying the government and justice act independently."The government always respects the judicial process," she told reporters. "Respecting the law is the first duty of those in power."